The present invention is related to a prefabricated outer wall structure with stress rupture resistance, particularly a prefabricated outer wall unit in which a silicone layer is defined between its inner material and outer decorative wall unit and a retention slot is formed between the inner material and the edge of the outer decorative wall unit, and an U-hook is placed in the retention slot for securing to a hook plate formed in a fixing component so that the fixing component is tightly secured to the construction.